1. Field of the Invention
The present invention relates to a silicone resin composition used in encapsulating an optical semiconductor element, a silicone resin sheet obtained by semi-curing the silicone resin composition, an optical semiconductor element device having an encapsulating layer obtained by curing the silicone resin composition, and a producing method of the silicone resin sheet.
2. Description of Related Art
Conventionally, a silicone resin with excellent transparency has been used as an encapsulating material for encapsulating an optical semiconductor element such as a light emitting diode (LED).
As such an encapsulating material, for example, a silicone resin composition containing an organopolysiloxane, which contains an alkenyl group, and an organohydrogenpolysiloxane has been known (ref: for example, Japanese Unexamined Patent Publications No. 2000-198930, No. 2004-186168, and No. 2008-150437).
The silicone resin composition is usually in a liquid state at room temperature, and the alkenyl group in the organopolysiloxane and a hydrosilyl group in the organohydrogenpolysiloxane are subjected to an addition reaction to be cured by heating in the presence of a platinum catalyst.
To encapsulate the optical semiconductor element using the silicone resin composition, for example, a method of filling the silicone resin composition in a housing in which the optical semiconductor element is disposed to be cured has been known.
However, in this method, there may be a case where viscosity of the silicone resin composition in a liquid state changes in accordance with the operating environment, so that it may be difficult to stably fill with the silicone resin composition.
Therefore, for example, a method of fabricating an optical semiconductor encapsulating sheet by heating and drying an encapsulating sheet composition, which contains a silicone resin having a cyclic ether-containing group (to be specific, a glycidyl group, an epoxycyclohexyl group, and an oxetane group) and a thermal curing agent that reacts with the cyclic ether-containing group, and encapsulating an optical semiconductor element using the optical semiconductor encapsulating sheet has been proposed (ref: for example, Japanese Unexamined Patent Publication No. 2009-84511).